This invention relates to ultrasonic surgical systems and, more particularly, to an improved apparatus for facilitating the performance of surgical procedures such as simultaneous soft tissue dissection and cauterization of large and small blood vessels through the use of a precisely controlled ultrasonically vibrating instrument, such as a blade or scalpel.
It is known that electric scalpels and lasers can be used as surgical instruments to perform the dual function of simultaneously effecting the incision and hemostatis of soft tissue by cauterizing tissues and blood vessels. However, such instruments employ very high temperatures to achieve coagulation, causing vaporization and fumes as well as splattering, which increases the risk of spreading infectious diseases to operating room personnel. Additionally, the use of such instruments often results in relatively wide zones of thermal tissue damage.
Cutting and cauterizing of tissue by means of surgical blades vibrated at high speeds by ultrasonic drive mechanisms is also well known. In such systems, an ultrasonic generator is provided which produces an electrical signal of a particular voltage, current and frequency, e.g., 55,500 cycles per second. The generator is connected by a cable to a handpiece, which contains piezoceramic elements forming an ultrasonic transducer. In response to a switch on the handpiece or a foot switch connected to the generator by another cable, the generator signal is applied to the transducer, which causes a longitudinal vibration of its elements. A structure connects the transducer to a surgical blade, which is thus vibrated at ultrasonic frequencies when the generator signal is applied to the transducer. The structure is designed to resonate at the selected frequency, thus amplifying the motion initiated by the transducer.
The blade is often non-symmetrical in shape and, during the surgical procedure, the physician manipulates the handpiece to cause the blade to contact the tissue to be treated. Because the switch which control operation of the blade is disposed on the handpiece, the location of the switch may at times prevent the physician from contacting tissue with the desired orientation of the blade because the relative position between the switch and the blade may prevent or render it difficult for the physician to manipulate the blade to the proper position while still being able to activate the switch with his/her fingers.
Thus, there is a need for a handpiece and switch assembly which will permit the physician to freely access tissue and operate thereon without having to worry about the relative position between the switch and the blade.
The present invention is directed towards a surgical instrument and, more particularly, to a surgical handpiece having a switch end cap detachably and rotatably connected to a handpiece body. Preferably, the surgical instrument comprises an ultrasonic surgical instrument which uses ultrasonic vibrations to perform a surgical operation. An instrument, such as a blade, e.g., a scalpel blade, is inserted and secured within the handpiece body so that a portion of the blade extends beyond the handpiece body for contacting tissue and the like. The switch end cap includes a switch mechanism having one or more switch button members for selectively signaling the level of power delivered to the handpiece from a power source, e.g., an external ultrasonic generator. Preferably, the switch mechanism includes at least two settings, namely a low power setting and a high power setting. When the high power setting is selected, the blade is ultrasonically vibrated at an elevated level and when the low power setting is selected, the blade is ultrasonically vibrated at a reduced level. The switch mechanism is actuated by pressing a portion of one switch button member depending upon whether high or low power is desired for the particular application.
In one exemplary embodiment, the handpiece body is coupled to the power source by a power cable which extends from one end of the handpiece body. The components for producing the ultrasonic vibrations include, but are not limited to, a transducer and a horn which is connected to the transducer at one end and to the blade at an opposite end. The blade preferably is easily attachable/detachable from the horn to permit the blade to be easily cleaned, serviced or replaced. The horn extends along a longitudinal axis of the handpiece body and at least a portion of the horn extends beyond the end of the handpiece body where it is coupled to the blade. This end of the handpiece body is configured to receive one end of the switch end cap in a releasably engaged manner. It will also be appreciated that the handpiece body and switch end cap may be semi-permanently or permanently connected to one another while still being rotatable relative to one another.
According to one aspect of the present invention, the handpiece body and the switch mechanism disposed within the switch end cap are electrically connected to one another in such a manner that permits the switch end cap may be freely rotated about the handpiece body while the electrical connection is maintained. This permits a user, e.g. a surgeon, to rotate the switch end cap during operation of the handpiece in order to position the switch end cap in an optimum position relative to the blade. Because the blade has a generally non-symmetrical nature, the surgeon may prefer to alter the relative position of the switch end cap with respect to the blade in order to conveniently contact tissue. The present invention provides such a feature and permits the surgeon to tailor the specific location of the switch end cap for and during a specific surgical operation.
In yet another aspect of the present invention, a seal member is disposed within the handpiece body and is preferably formed of an elastic material which intimately engages a sheath portion of the blade to form a seal therebetween. The seal member prevents unwanted foreign material from entering the inside of the switch end cap and making contact with the switch mechanism or other internal components. In a preferred embodiment, the seal member comprises an annular seal member which is concentrically disposed relative to the sheath of the blade to form the seal therebetween. The sheath member is also preferably formed of an elastic material which permits an effective seal to be formed.